Large-compensation constant-pressure pre-tightening structure for deep hypothermia

Abstract

The invention relates to a large-compensation constant-pressure pre-tightening structure for deep hypothermia, and belongs to the technical field of spaceflight optical remote sensors. Comprising an Invar substrate, a heat conduction chain, an Invar pressing plate and six groups of pre-tightening pieces, wherein the Invar substrate is of a horizontally placed plate-shaped structure; a groove is formed in the upper surface of the Invar substrate; the heat conduction chain is filled in the groove of the Invar substrate; the Invar pressing plate horizontally covers the upper surface of the heat conduction chain; the six groups of pre-tightening pieces are distributed on the upper surface of the Invar pressing plate in a 2 * 3 matrix; the six groups of pre-tightening pieces are vertically arranged; the pre-tightening piece sequentially penetrates through the Invar pressing plate and the heat conduction chain from top to bottom, and the bottom of the pre-tightening piece extends into the Invar substrate; the problem of low-temperature unloading in the low-temperature optical system is solved, and the low-temperature performance of the optical system is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace optical remote sensors and relates to a large compensation constant pressure pre-tightening structure for deep low temperature. Background Art

[0002] In order to achieve high-sensitivity and high-precision detection of targets. Low-temperature infrared cameras in medium and low orbits require detectors to work stably in a deep low-temperature 40K environment to ensure the camera's imaging quality and meet detection sensitivity requirements. The traditional common coupling method for domestic detectors is to connect them through an epoxy adhesive bonding process. At present, this process has hidden dangers such as mismatched thermal expansion coefficients of materials inside the detector, resulting in large differences in stress gradients in the structure and difficulties in implementing the bonding process. When the tensile stress in the surrounding local stress concentration area is greater than the tensile strength of the material, crack defects will occur. Most domestic detectors are coupled in this way. However, the deep low temperature of 40K makes the thermal mismatch between the chip and the Invar substrate cold stage more prominent. Therefore, ensuring the low temperature of the optical structure is a difficulty in the development of space optical cameras. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art, to propose a large compensation constant pressure pre-tightening structure for deep cryogenics, to solve the problem of low temperature unloading in a low temperature optical system, and to ensure the low temperature performance of the optical system.

[0004] The solution of the present invention is:

[0005] A large compensation constant pressure pre-tightening structure for deep low temperature, comprising an Invar base plate, a heat transfer chain, an Invar pressure plate and n groups of pre-tightening parts;

[0006] Among them, the Invar substrate is a horizontally placed plate-like structure; a groove is arranged on the upper surface of the Invar substrate; the thermal conductive chain is filled in the groove of the Invar substrate; the Invar pressing plate is horizontally covered on the upper surface of the thermal conductive chain; n groups of pre-tightening members are all placed vertically; the pre-tightening members pass through the Invar pressing plate and the thermal conductive chain from top to bottom in sequence, and the bottom of the pre-tightening members extends into the Invar substrate.

[0007] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, the n is 6; the 6 groups of pre-tightening parts are distributed on the upper surface of the Invar pressure plate in a 2×3 matrix.

[0008] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, the pre-tightening member includes a compression stud, a butterfly spring and a nut;

[0009] Among them, the clamping stud is a vertical rod-shaped structure; the clamping stud passes through the Invar pressure plate and the heat transfer chain from top to bottom in sequence, and the bottom of the clamping stud extends into the Invar base plate; the butterfly spring is sleeved on the outer wall of the clamping stud, and the butterfly spring is located on the upper surface of the Invar pressure plate; the nut is sleeved on the outer wall of the clamping stud and is located above the butterfly spring.

[0010] In the above-mentioned large compensation constant pressure preload structure for deep low temperature, the butterfly spring is made of titanium alloy material to achieve normal operation in a 40K deep low temperature environment.

[0011] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, a pre-tightening force is provided between the Invar base plate, the heat transfer chain and the Invar pressure plate through a butterfly spring.

[0012] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, the clamping stud cooperates with the nut thread, and the heat-conducting chain and the Invar pressing plate are pressed into the groove of the Invar substrate through the nut.

[0013] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, the Invar pressure plate and the clamping stud are clearance-matched; when working in a 40K deep low temperature environment, the heat transfer chain contracts due to the cold, and the Invar pressure plate moves horizontally by the gap distance and moves relative to the clamping stud.

[0014] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, the thickness of the heat-conducting chain is 16 mm.

[0015] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, the shrinkage amount of the heat-conducting chain in the thickness direction is 0.2-0.3mm in the 40K temperature range, and the thermal conductivity is 950-1000W / m·K.

[0016] In the above-mentioned large compensation constant pressure pre-tightening structure for deep low temperature, the butterfly spring has a size of 3.2mm×8mm×1mm. In a low temperature environment of 40K, the contraction of the heat conductive chain is compensated by the deformation of the butterfly spring.

[0017] The beneficial effects of the present invention compared with the prior art are:

[0018] (1) The present invention can provide a stable, deep-cryogenic temperature environment guarantee for space remote sensor detectors. The deep-cryogenic detector based on butterfly springs uses a large temperature difference compensation structure, which can better solve the problem of deep-cryogenic thermal compensation deformation.

[0019] (2) In order to ensure good contact, the present invention needs to ensure sufficient pressing force at a deep low temperature of 40K. Therefore, a compensation structure that is used at a temperature of 40K and meets application requirements is designed to compensate for the shrinkage deformation of the cold chain under low temperature conditions and ensure a good heat transfer state;

[0020] (3) The present invention adopts a constant pressure preload structure, and is used as a compensation part for coupling the infrared detection system detector assembly with the cold chain. It is necessary to ensure that the high thermal conductivity heat chain coupling contact part has good pressing strength at low temperature 40K. Titanium alloy butterfly springs have the advantages of good low temperature performance, easy processing, high mechanical strength, good chemical stability, and no magnetism (to avoid affecting the detector signal);

[0021] (4) The present invention utilizes the elastic deformation characteristics of the titanium alloy butterfly spring to solve the key problem of difficulty in unloading due to large differences in the linear expansion coefficient of the material at deep low temperature of 40K. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a top view of the large compensation constant pressure pre-tightening structure for deep low temperature of the present invention;

[0023] Figure 2 It is a side cross-sectional view of the large compensation constant pressure pre-tightening structure for deep low temperature of the present invention;

[0024] Figure 3 This is a detailed cross-sectional view of the large compensation constant pressure pre-tightening structure for deep low temperature use of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments.

[0026] The present invention provides a large compensation constant pressure pre-tightening structure for deep cryogenics, which effectively improves the thermal conductivity reliability of the detector under deep cryogenics. The structure can be applied to the unloading compensation part of deep cryogenic optical parts, effectively reducing the influence of the deep cryogenic surface topography on imaging.

[0027] Large compensation constant pressure preload structure for deep low temperature, such as Figure 1 , Figure 2 , Figure 3 As shown, it specifically includes an Invar substrate 1, a heat-conducting chain 2, an Invar pressing plate 4 and n groups of pre-tightening parts.

[0028] The Invar substrate 1 is a horizontally placed plate-like structure; a groove is provided on the upper surface of the Invar substrate 1; the heat-conducting chain 2 is filled in the groove of the Invar substrate 1; the Invar pressing plate 4 is horizontally covered on the upper surface of the heat-conducting chain 2; n groups of pre-tightening parts are all placed vertically; the pre-tightening parts pass through the Invar pressing plate 4 and the heat-conducting chain 2 from top to bottom, and the bottom of the pre-tightening parts extends into the Invar substrate 1. n is 6; the 6 groups of pre-tightening parts are distributed on the upper surface of the Invar pressing plate 4 in a 2×3 matrix.

[0029] The pre-tightening part includes a clamping stud 3, a butterfly spring 5 and a nut 6. The clamping stud 3 is a vertical rod-shaped structure; the clamping stud 3 passes through the Invar pressing plate 4 and the heat-conducting chain 2 from top to bottom, and the bottom of the clamping stud 3 extends into the Invar base plate 1; the butterfly spring 5 is sleeved on the outer wall of the clamping stud 3, and the butterfly spring 5 is located on the upper surface of the Invar pressing plate 4; the nut 6 is sleeved on the outer wall of the clamping stud 3 and is located above the butterfly spring 5.

[0030] The butterfly spring 5 is made of titanium alloy material to achieve normal operation in a deep low temperature environment of 40 K. Through the butterfly spring 5, a pre-tightening force is provided between the Invar substrate 1, the heat transfer chain 2, and the Invar pressure plate 4.

[0031] The clamping stud 3 is threadably matched with the nut 6 , and the nut 6 is used to clamp the heat conducting chain 2 and the Invar pressing plate 4 into the groove of the Invar substrate 1 .

[0032] There is a clearance fit between the Invar pressing plate 4 and the clamping stud 3; when working in a deep low temperature environment of 40K, the heat transfer chain 2 contracts due to the cold, and the Invar pressing plate 4 moves horizontally by a gap distance and moves relative to the clamping stud 3.

[0033] The thickness of the heat-conducting chain 2 is 16 mm. The shrinkage amount of the heat-conducting chain 2 in the thickness direction is 0.2-0.3 mm at a temperature of 40K, and the thermal conductivity is 950-1000 W / m·K.

[0034] The size of the butterfly spring 5 is 3.2 mm×8 mm×1 mm. In a low temperature environment of 40K, the contraction of the heat-conducting chain 2 is compensated by the deformation of the butterfly spring 5 .

[0035] The clamping stud 3 is pre-installed on the Invar substrate 1, and then the high thermal conductivity heat chain 2 is installed on the Invar substrate 1. By pre-tightening the titanium alloy butterfly spring 5, a certain pre-tightening force is guaranteed for the Invar substrate 1, the Invar pressure plate 4 and the high thermal conductivity heat chain 2. At the same time, the high thermal conductivity heat chain 2 can deform at a low temperature of 40K and move relatively with the Invar substrate 1 and the Invar pressure plate 4, forming a self-balancing internal force distribution of the system, ensuring the stability of the structural shape and position tolerance of the Invar substrate 1, and solving the deep low temperature thermal compensation problem.

[0036] The present invention provides a large compensation constant pressure pre-tightening structure for deep low temperature, which solves the key problem of difficulty in unloading caused by large differences in material linear expansion coefficients at deep low temperature of 40K in the detector, and ensures the low temperature performance of the optical system. The titanium alloy butterfly spring is a high-performance titanium alloy butterfly spring that can withstand deep low temperature of 40K, so that the structure can be installed and pressed by the Invar substrate, clamping studs, Invar pressure plates, and nuts at low temperature of 40K, ensuring good contact and achieving higher thermal capacity.

[0037] The present invention can provide a stable, deep-cryogenic temperature environment guarantee for a space remote sensor detector. The deep-cryogenic detector based on a butterfly spring uses a large temperature difference compensation structure and can better solve the problem of deep-cryogenic thermal compensation deformation.

[0038] The infrared camera system has strict requirements on the contact resistance of heat conduction between the detector and the cold chain. To ensure good contact, it is necessary to ensure sufficient pressing force at the deep low temperature of 40K. Therefore, a compensation structure that can be used under 40K temperature conditions and meet application requirements is needed to compensate for the shrinkage and deformation of the cold chain under low temperature conditions and ensure good heat transfer.

[0039] The present invention adopts a constant pressure preload structure, and is used for the compensation parts of the infrared detection system detector assembly and the cold chain coupling. It is necessary to ensure that the high thermal conductivity heat chain coupling contact part has good pressing strength at low temperature 40K. Titanium alloy butterfly springs have good low temperature performance, easy processing, high mechanical strength, good chemical stability, and no magnetism (to avoid affecting the detector signal). The elastic deformation characteristics of titanium alloy butterfly springs are used to solve the key problem of difficulty in unloading due to large differences in material linear expansion coefficients at deep low temperature 40K.

[0040] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A large compensation constant pressure preload structure for deep low temperature, characterized by: It comprises an Invar base plate (1), a heat conducting chain (2), an Invar pressing plate (4) and n groups of pre-tightening parts; The Invar substrate (1) is a horizontally placed plate-like structure; a groove is provided on the upper surface of the Invar substrate (1); the heat-conducting chain (2) is filled in the groove of the Invar substrate (1); the Invar pressing plate (4) is horizontally covered on the upper surface of the heat-conducting chain (2); the n groups of pre-tightening members are all placed vertically; the pre-tightening members pass through the Invar pressing plate (4) and the heat-conducting chain (2) in sequence from top to bottom, and the bottom of the pre-tightening members extends into the Invar substrate (1).

2. A large compensation constant pressure preload structure for deep cryogenic use according to claim 1, characterized in that: The number n is 6; the 6 groups of pre-tightening members are distributed on the upper surface of the Invar pressing plate (4) in a 2×3 matrix.

3. The large compensation constant pressure preload structure for deep cryogenic use according to claim 1, characterized in that: The pre-tightening member comprises a pressing stud (3), a butterfly spring (5) and a nut (6); The clamping stud (3) is a vertical rod-shaped structure; the clamping stud (3) passes through the Invar pressure plate (4) and the heat transfer chain (2) from top to bottom, and the bottom of the clamping stud (3) extends into the Invar base plate (1); the butterfly spring (5) is sleeved on the outer wall of the clamping stud (3), and the butterfly spring (5) is located on the upper surface of the Invar pressure plate (4); the nut (6) is sleeved on the outer wall of the clamping stud (3) and is located above the butterfly spring (5).

4. A large compensation constant pressure preload structure for deep cryogenic use according to claim 3, characterized in that: The butterfly spring (5) is made of titanium alloy material to achieve normal operation in a 40K deep cryogenic environment.

5. A large compensation constant pressure pre-tightening structure for deep low temperature according to claim 4, characterized in that: The butterfly spring (5) is used to provide a pre-tightening force between the Invar base plate (1), the heat conducting chain (2) and the Invar pressure plate (4).

6. A large compensation constant pressure preload structure for deep cryogenic use according to claim 3, characterized in that: The clamping stud (3) is threadably matched with the nut (6), and the nut (6) is used to clamp the heat-conducting chain (2) and the Invar pressing plate (4) into the groove of the Invar base plate (1).

7. The large compensation constant pressure pre-tightening structure for deep cryogenic use according to claim 3 is characterized in that: The Invar pressing plate (4) and the clamping stud (3) are clearance-matched; when working in a 40K deep low temperature environment, the heat conducting chain (2) contracts due to the cold, and the Invar pressing plate (4) moves horizontally by a clearance distance and moves relative to the clamping stud (3).

8. The large compensation constant pressure pre-tightening structure for deep cryogenic use according to claim 7, characterized in that: The thickness of the heat-conducting chain (2) is 16 mm.

9. A large compensation constant pressure pre-tightening structure for deep cryogenic use according to claim 8, characterized in that: The heat-conducting chain (2) has a shrinkage amount of 0.2-0.3 mm in the thickness direction at a temperature of 40K, and a thermal conductivity of 950-1000 W / m·K.

10. A large compensation constant pressure pre-tightening structure for deep cryogenic use according to claim 9, characterized in that: The butterfly spring (5) has a size of 3.2 mm×8 mm×1 mm. In a low-temperature environment of 40 K, the contraction of the heat-conducting chain (2) is compensated by the deformation of the butterfly spring (5).

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